Commands by op4 (7)

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pretend to be busy in office to enjoy a cup of coffee
Create a progress dialog with custom title and text using zenity.

tcpdump sniff pop3,imap,smtp and http

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Migrate Server with rsync
Copies the complete root-dir of a linux server to another one, where the new harddisks formated and mountet. Very useful to migrate a root-server to another one.

Recursively search and replace old with new string, inside every instance of filename.ext
This is a slightly modified version of http://www.commandlinefu.com/commands/view/4283/recursive-search-and-replace-old-with-new-string-inside-files (which did not work due to incorrect syntax) with the added option to sed inside only files named filename.ext

dstat - a mix of vmstat, iostat, netstat, ps, sar...
This is a very powerful command line tool to gather statistics for a Linux system. http://dag.wieers.com/home-made/dstat/

Check whether IPv6 is enabled
Checks whether IPv6 is enabled system-wide by reading from procfs.

check for write/read permissions
su www-apache/ftp user and then check readable: find ~/ -type d \( -wholename '/dev/*' -o -wholename '/sys/*' -o -wholename '/proc/*' \) -prune -o -exec test -r {} \; -exec echo {} readable \; 2>/dev/null check writable: find ~/ -type d \( -wholename '/dev/*' -o -wholename '/sys/*' -o -wholename '/proc/*' \) -prune -o -exec test -w {} \; -exec echo {} writable \; 2>/dev/null

list file descriptors opened by a process
Useful for examining hostile processes (backdoors,proxies)

Put split files back together, without a for loop
After splitting a file, put them all back together a lot faster then doing $cat file1 file2 file3 file4 file5 > mainfile or $for i in {0..5}; do cat file$i > mainfile; done When splitting, be sure to do split -d for getting numbers instead of letters


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